The present invention relates to a display driver, a display unit, and an electronic instrument.
Taking a mobile telephone as an example of an electronic instrument, a technique has been proposed for receiving or transmitting image data that has been compressed and encoded in accordance with the Moving Picture Experts Group (MPEG) standard. Such a technique makes it possible to display a moving image in a display area of a display section that is used for a still image in the art, by way of example.
In this example of a portable telephone, still-image data, which is a part of the image data to be displayed on the display section that involves a particularly light processing load, is generated by a central processing unit (CPU) that controls the portable telephone itself. The thus-generated still-image data is sent to a display data RAM and is read out in units of one scan line every frame period, by way of example. This reduces the processing load of the CPU and promotes a reduction in power consumption.
Moving-image data, on the other hand, involves processing that is large-scale and necessitates real-time capabilities, which means that a dedicated controller such as a digital signal processor (DSP) is provided separately from the CPU that has to handle processes such as the transfer of other data and the actual telephony, and the moving-image data is generated by that controller. The moving-image data could also be transferred to the above-described display data RAM, but it is possible to avoid complicating the circuitry required for simultaneous processing with the still-image data and also reduce the power consumption by using a one-scan-line memory that stores only data for one scan line.